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General => General Discussion => Topic started by: pinarelloman on August 02, 2015, 10:13:14 AM

Title: Welding on to gal?
Post by: pinarelloman on August 02, 2015, 10:13:14 AM
I want to weld my homemade high lift jack holder onto my Kaymar spare wheel locking plate. IE the one you put the padlock through so no one can steal your spare wheel off the back.
It is galvanised and I was wondering how you weld onto gal. I tried on something once before and it spits and pops.

As this is structural in that I dont want the high lift falling off, how do i do it?
Just grind the gal back and weld away? Do I need to grind all the gal off, or just the surface?
Title: Re: Welding on to gal?
Post by: Andy_Q on August 02, 2015, 10:25:57 AM
You do need to grind back the gal in the area you are welding. I'd use a flap disk for the job.
Once you have ground back to bare steel you should be  ok.


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Title: Re: Welding on to gal?
Post by: oldmate on August 02, 2015, 10:58:16 AM
As above. Then I normally hit with some cold gal in a pressure pack can after weld has cooled
Title: Re: Welding on to gal?
Post by: sparksy on August 02, 2015, 11:06:39 AM
Weld it in a ventilated area. The fumes given off by the galv are toxic.
Title: Re: Welding on to gal?
Post by: champin on August 02, 2015, 03:40:35 PM
If you can, grab a tin of cold gal. Way better than the aerosol. In fact its almost as good as hot dip. The older and gluggier the better it is.
Title: Re: Welding on to gal?
Post by: Metters on August 02, 2015, 03:44:56 PM
You can weld over gal on mild steel and it is not likely to break but, as has already been said, the fumes are toxic and it will spit.

I was working for a large structural steel fabrication company in Wagga Wagga around 1980 when the company got the contract to build 2000 galvanised gates and many hundreds of fence panels for the new cattle sale yards at Bowen just north of the city.  Two of us started by building an elaborate jig for the gates.  I welded one side then flipped the gate over and slid it down a short ramp so the other man could weld the other side.   I calculated we each did around 75,000 welds.  All of the welding was done with 320 amp MIGs and CO2 gas which makes the spitting even worse.

We would still be building them if we ground the gal off first.   To protect ourselves we wore twin filter respirators and used a big industrial fan positioned behind us so we could use our bodies to shield the weld gas from the fast moving air.  I always held my breath during each weld then moved slightly allowing the fan to clear the fumes instantly.

It worked, we both survived and we consistently made 60 gates a day.

For a little one off job like yours, I would simply grind the gal off.  I have done this many times at home on small projects and it usually only takes a few seconds. 

Title: Re: Welding on to gal?
Post by: graham on August 02, 2015, 06:10:56 PM
Don't be scared to grind the crap out of it ,before you weld it
Are we talking the gal that is silver in colour  ,Or is it the gold cad plating found on most parts nowadays
Not that it matters too much as you should be joining two clean bits of metal together, no paint/plating
Cheers
Title: Re: Welding on to gal?
Post by: Troopy_03 on August 03, 2015, 11:54:31 AM
And hit it with the cold gal while it is still pretty warm. Not super hot, but just hot enough so you can barely handle it. Makes it set on hard.
Title: Re: Welding on to gal?
Post by: pinarelloman on August 03, 2015, 05:15:13 PM
Thanks guys, hit it with the grinder then welded the high lift jack bracket to it. It did not spit as much as I thought.
Quite happy with the welding. The last one didn't fall off with my crappy welds, so this one will be ok.
Thanks for the advice.